Bridging the gap between chewing and sucking in the hemipteroid insects: new insights from Cretaceous amber
Author
Yoshizawa, Kazunori
Author
Lienhard, Charles
text
Zootaxa
2016
4079
2
229
245
journal article
31519
10.11646/zootaxa.4079.2.5
4b323554-9845-4c4b-b4f7-73b88422eaae
1175-5326
1050645
91DF9041-B3CD-49E9-8250-D0C251938B45
Mydiognathus eviohlhoffae
n. sp.
(
Figs 1
,
2
a–c, 3a–c)
Description
.
Head
(
Figs 1
a–d, 2a–c). Hypognathous, detached from thorax. Vertex rounded, protruding dorsally; medially concave along occipital suture. Frons bulbous. Frontogenal suture directed backward from anterior tentorial pit along ventral head capsule then strongly curved dorsally, ending between eye and antennal socket. Gena expanded laterally. Eye large; three ocelli, each on a tubercle. Postclypeus not expanded dorsally, not bulged; anteclypeus less sclerotized, with pair of swellings laterally. Antennal socket strongly pedicellate. Antenna filiform, with at least 16 articles; scape nearly cylindrical; pedicel strongly constricted basally, cylindrical distally, with bifurcated tip; flagellum long, far exceeding forewing length, no rupturing mechanism recognizable; flagellomeres annulate except for first one (f1) and basal half of f2. Labrum much longer than wide, apically rounded, covering entire elongated mandibles anteriorly. Mandibles elongate, apically curved inwardly, with two subapical conical teeth; basally broadened, with asymmetrical molar area internally. Maxillae elongate, symmetrical; cardo strip-like, projecting outward posteriorly; stipes bulged posteriorly and laterally; galea clearly separated from stipes, flattened apically and curved internally; lacinia stylet-like, apically curved posterointernally, basally extended deeply into head capsule; palpus four segmented, second and fourth articles especially long, inner surface of terminal article flattened; palpifer well developed. Hypopharynx elongate, apically exceeding base of labial palpus; anterior surface with keel along median line, placed between lacinial stylets. Labium elongate, medially concave forming groove housing elongated hypopharynx and lacinial stylets; paraglossa present; glossa absent; palpus four segmented (or three if the most basal tiny article represents palpifer).
Thorax
(
Fig. 1
a,b). Prothorax small, detached from mesothorax. Meso- and metathorax fused, analogous in structures, well developed, bulged dorsally; scutum bilobed; scutellum pentagonal in shape; basalare well differentiated from episternum; anapleural suture not visible; posterior margin of epimeron protruding medially.
FIGURE 1.
Photographs of
Mydiognathus eviohlhoffae
. (a) Habitus, right view. (b) Habitus, left view. (c) Head. (d) Connection between first (top) and second antennal flagellomeres. (e) Right hind tarsus, ventral view.
FIGURE 2.
Key head structures of
Mydiognathus eviohlhoffae
(a–c) and
Neotrogla aurora
(d). (a) Head. Dotted gray lines indicate alignment of mouthpart structures against the labrum (Lr) or lacinia (Lc, only for galea: Ga) (Acl: anteclypeus; At: antenna; ATP: anterior tentorial pit; Ca: cardo; E: eye; ES: epistomal suture; FGR: frontogenal suture; Fr: frons; Ga: galea; Ge: gena; Lc: lacinia; LiP: labial palpus; Lr: labrum; Md: mandible; MxP: maxillary palpus; Oc: ocellus; Pcl: postclypeus; Pf: palpifer; Pg: paraglossa; St: stipes). (b) Head, magnified. White arrowheads indicate the internally expanded lacinial base. (c) Tip of the mouth, magnified. (d) Antennal flagellum of
Neotrogla aurora
(
Psocodea
: Trogiomorpha:
Prionoglarididae
), showing the rupturing mechanism observed in extant
Psocodea
.
Wings
(
Figs 1
a,b, 3a). Membrane and veins of both wings evenly covered by microtrichia; margins setose. Forewing transparent with broad blackish brown region anteroproximally; Sc short, ending on anterior margin; pterostigma darkly pigmented but not significantly thickened; nodus and nodulus (fore- and hindwings coupling mechanism) absent; venation as indicated for family (
Vishniakova 1976
;
Huang
et al
. 2008
) and genus (see above); bases of Cu veins obscure. Hindwing slightly smaller and very similar to forewing, but areola postica absent.
Forewing base articulations
(
Fig. 3
b,c). Tips of ANWP and MNWP invisible. PNWP narrow and long, tightly articulated with 3Ax. Tg well developed. HP and BSc fused. BSc and 2Ax separated by BR. First axillary sclerite hardly visible. Anterior region of 2Ax strongly swollen, divided into two sclerites; posterior region small and triangular, articulated with 3Ax. Proximal and distal arms of 3Ax short, anterior arm long. PMP deeply concave, distal margin strongly sclerotized, anteroproximal region broadly membranous, fused to BA posteriorly and distally. DMP small, located next to 2Ax.
Legs
(
Fig. 1
a,b,e). All legs analogous in structures; hind leg significantly longer than other legs but no specialization detected (e.g. for jumping). Coxae well developed, no specialization on internal surface of hind coxae. Tibiae with two well-developed tibial spurs distally. Tarsi four segmented; pretarsal claws symmetrical, without preapical tooth, with well-developed arolium between them.
FIGURE 3.
Illustrations of key wing structures in
Mydiognathus eviohlhoffae
(a–c) and other insect orders (d–f). (a) Forewing (composite drawing reconstructed from distal half of right forewing and basal half of left forewing). (b) Left forewing base articulation. (c) Right forewing base articulation. Forewing base articulation d–f: (d)
Alloperla
sp. (
Plecoptera
), (e)
Longivalvus nubilus
(Psocodea)
, (f)
Petalolyma bicolor
(Hemiptera)
.
FIGURE 4.
Male terminalia of
Mydiognathus eviohlhoffae
(St: sternite; T: tergite; Ad: aedeagus; Ep: epiproct; Pa: paraproct; Tr: trichobothria).
Abdomen
(
Figs 1
a,b, 4). Weakly sclerotized, tergum and sternum well differentiated. First abdominal tergite clearly differentiated from second segment; sternite 1 not clearly differentiated. Terminal segments well sclerotized. Epiproct convex dorsally, pointed posteriorly. Paraproct rounded posteriorly, with swollen trichobothrial field. Ninth sternum strongly protruding posteriorly, genital chamber broadly open dorsally. Aedeagus pointed apically.
Lengths
(seen from right side, in mm). Body 2.12; antennal flagellomere f1 0.60, f2 0.56, f3 0.61; forewing 2.38, hindwing 2.20; hind femur 0.68, hind tibia 1.26, hind tarsus t1 0.38, t2 0.16, t3 0.05, t4 0.06.
Holotype
.
Male
. Embedded in Burmite, early Cenomanian (Upper Cretaceous, ca. 99 Mya:
Shi
et al
. 2012
), Hukawng Valley, northern
Myanmar
(to be deposited in State Museum of Natural History in Stuttgart,
Germany
, under specimen
ID
SMNS
Bu-174).
Etymology
. The specific epithet honours Evi Ohlhoff, wife of Rainer Ohlhoff (who made the specimen available for study) and codiscoverer of the specimen.